Messages in this thread | | | From | Yury Norov <> | Subject | [PATCH v2 0/5] lib/find: add find_nth_bit() | Date | Sun, 10 Jul 2022 21:47:06 -0700 |
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Kernel lacks for a function that searches for Nth bit in a bitmap. Usually people do it like this: for_each_set_bit(bit, mask, size) if (--n == 0) return bit;
Which is not so elegant, and very slow.
This series adds fast routines for this task, and applies them where appropriate.
While here, move thin wrappers around find_bit() in nodemask.c to a corresponding header, and because nodemask.c is empty after that, remove it.
v1: https://lore.kernel.org/lkml/20220706182300.70862-4-yury.norov@gmail.com/T/ v2: - count Nth bit from 0 (was 1); - use 'invert' trick in _find_nth_bit(), as in _find_next_bit(); - cleanup comments; - fns() is kept inline - looking at __ffs() generic implementation, I decided to keep it untouched.
Yury Norov (5): lib: add find_nth(,and,andnot)_bit() lib/bitmap: add tests for find_nth_bit() lib/bitmap: remove bitmap_ord_to_pos cpumask: add cpumask_nth_{,and,andnot} lib/nodemask: inline next_node_in() and node_random()
MAINTAINERS | 1 - include/linux/bitmap.h | 1 - include/linux/bitops.h | 19 +++++++++ include/linux/cpumask.h | 44 +++++++++++++++++++++ include/linux/find.h | 83 ++++++++++++++++++++++++++++++++++++++++ include/linux/nodemask.h | 27 ++++++++++--- lib/Makefile | 2 +- lib/bitmap.c | 36 ++--------------- lib/cpumask.c | 26 ++++++------- lib/find_bit.c | 20 ++++++++++ lib/find_bit_benchmark.c | 17 ++++++++ lib/nodemask.c | 31 --------------- lib/test_bitmap.c | 36 ++++++++++++++++- 13 files changed, 254 insertions(+), 89 deletions(-) delete mode 100644 lib/nodemask.c
-- 2.34.1
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